Sunderland striker Michael Reddy is running out of time in a bid to realise his World Cup dream after it emerged that the Irishman faces further treatment on his troublesome hamstring.

Black Cats' boss Peter Reid last night admitted that the 21-year-old has been plagued by the same injury for too long and the highly-rated forward will seek further medical advice this week.

Reddy had hoped to make a first-team breakthrough this season and, at the same time, force his way into Mick McCarthy's Republic of Ireland squad.

Now neither ambition looks like being fulfilled as the former Kilkenny City forward faces an uncertain future and a seemingly tough battle back to full fitness.

"Michael has hurt his hamstring again and it is a real problem," confessed Reid as he finalised plans for tomorrow's trip to Southampton.

"We need to get it sorted out because the lad's been struggling with the same problem for too long now."

Reddy returned to Wearside from Hull last month with high hopes after scoring four goals in five games for Brian Little's men. The Under-21 international won rave reviews the previous season during a successful loan spell with Swindon and was expected to push for a first-team place with Sunderland in the New Year.

Reddy had always earmarked this season as a breakthrough campaign and Irish officials had hoped he would be in a position to bolster the senior ranks, if required, at next summer's World Cup.

Certainly the young striker looked set to make a big impression on the domestic and international stage when he burst on to the Premiership scene at the tender age of 19, going on to play seven league games for the Black Cats in the 1999-2000 season.

It was towards the end of that campaign that Reddy's hamstring injury first struck and, despite showing flashes of his best form in the following months, it has overshadowed his progress ever since.

Reyna has trained relatively freely all week despite suffering from a slight groin strain and the American midfielder, who came second in Wednesday night's USA Player of the Year poll, is keen to make his debut against Gordon Strachan's men.

"The players who faced Chelsea performed particularly well," said Reid.

"I have a serious selection headache in midfield and the players who are in possession of shirts quite rightly believe they deserve to be there again."